Large-tonnage steel cover beam construction method for miscellaneous fill geology and bridge

Abstract

The invention discloses a construction method for a large-tonnage steel cover beam in miscellaneous fill geology and a bridge, and relates to the field of bridge construction.The construction method for the large-tonnage steel cover beam in miscellaneous fill geology comprises the steps that undisturbed soil obtained after leveling excavation is subjected to layered pad replacement and top sealing pouring treatment; the compaction degree of the cushion changing layer on the lower layer is greater than that of the cushion changing layer on the upper layer; hoisting the steel cover beam sections to a pre-arranged mounting pedestal, establishing a plane coordinate and elevation measurement and control net taking the bridge as a main body, and assembling the steel cover beam sections to form a complete steel cover beam by taking the plane coordinate and the elevation measurement and control net as references; and a pier column is poured on the undisturbed soil subjected to top sealing pouring treatment, the complete steel cover beam is hoisted to the top of the pier column, and the installation elevation of the complete steel cover beam is adjusted to the designed elevation through a jacking mechanism located at the top of the pier column. And the influence on the existing business line is reduced to the maximum extent.

Description

Technical Field

[0001] The invention relates to the field of bridge construction, and in particular to a construction method for a large-tonnage steel cap beam in miscellaneous fill geology and a bridge. Background Art

[0002] Steel cap beam, that is, steel cap beam, refers to the beam set on the top of the frame pile pier to support, distribute and transfer the load of the superstructure, also known as cap beam. In bridge engineering, cap beam, box beam, pier column, etc. are all part of the main structure of the bridge and are indispensable parts. Large-tonnage steel cap beams are usually heavy. For example, the steel cap beams in some projects even exceed a total length of 30 meters and weigh up to 219 tons.

[0003] Due to the weight and size of large-tonnage steel cap beams, their transportation, installation and construction control are relatively difficult, especially for large-tonnage steel cap beams under the restricted conditions of railway operating lines. Their installation foundation is relatively loose and their bearing capacity is limited. At the same time, the lifting space and construction time are greatly restricted, which not only seriously affects the installation efficiency and installation accuracy of the steel cap beams, but also affects the existing operating lines in a vicious cycle. Summary of the invention

[0004] The present application provides a construction method and bridge for large-tonnage steel cap beams in miscellaneous fill geology, which can solve the technical problems existing in the prior art of large-tonnage steel cap beams under the restricted conditions of railway operating lines, such as loose installation foundations and limited bearing capacity, and greatly limited lifting space and construction time, which seriously affect the installation efficiency and installation accuracy of the steel cap beams and also affect the operating railways.

[0005] In a first aspect, an embodiment of the present application provides a method for constructing a large-tonnage steel cap beam in miscellaneous fill geology, comprising:

[0006] After leveling and excavation, the original soil is replaced by layers and capped with cast concrete, and the compaction degree of the replacement layer at the lower layer is greater than that of the replacement layer at the upper layer;

[0007] Lift the steel cap beam segments to the pre-arranged liftable installation pedestal, establish a plane coordinate and elevation measurement and control network with the bridge as the main body, and assemble the steel cap beam segments to form a complete steel cap beam based on the plane coordinate and elevation measurement and control network;

[0008] Cast the pier on the original soil after the capping pouring treatment, hoist the complete steel cap beam to the top of the pier, and adjust the installation elevation of the complete steel cap beam to the designed elevation through the jacking mechanism located at the top of the pier.

[0009] In combination with the first aspect, in one embodiment, before excavating the original soil, the method further includes:

[0010] Based on the design dimensions, process the various component plates of the steel cap beam segment;

[0011] Based on the installation sequence, each component plate is placed on the installation frame and fixed to form a single steel cap beam segment, wherein the ends of each component plate after fixing are spaced a certain distance apart;

[0012] The next steel cap beam segment is installed and fixed based on the previous fixed steel cap beam segment.

[0013] In one embodiment, the original soil after leveling and excavation is subjected to layered cushion replacement and capping pouring, and the compaction degree of the cushion replacement layer at the lower layer is greater than that of the cushion replacement layer at the upper layer, specifically including:

[0014] Based on the design drawings, excavate the original soil to a certain depth to form a foundation pit;

[0015] Level and compact the foundation pit and test the bearing capacity of the foundation in the foundation pit to ensure that the bearing capacity of the foundation meets the bearing requirements;

[0016] Fill and compact the replacement cushion material in the foundation pit to form a replacement cushion layer, and test the bearing capacity of the replacement cushion layer;

[0017] Using the lower replacement bedding layer that has been replaced as the base, fill the upper replacement bedding layer until multiple replacement bedding layers are formed, wherein the compaction degree of the replacement bedding layer at the lower layer is greater than that of the replacement bedding layer at the upper layer;

[0018] Pour the concrete above the topmost replacement pad.

[0019] In one embodiment, the steel cap beam segments are hoisted to a pre-arranged liftable mounting pedestal, a plane coordinate and elevation measurement and control network with the bridge as the main body is established, and the steel cap beam segments are assembled to form a complete steel cap beam based on the plane coordinate and elevation measurement and control network, specifically including:

[0020] Arrange a liftable installation pedestal at the construction site so that the axial length of the installation pedestal is longer than the axial length of the complete steel cap beam, and hoist the steel cap beam segments onto the installation pedestal in sequence;

[0021] Based on the design drawings and using surveying equipment, a plane coordinate and elevation measurement and control network with the bridge as the main body is established at the construction site;

[0022] Using the plane coordinates and the height measurement and control network as the control reference, adjust the lifting height of the installation pedestal to independently adjust the elevation and horizontality of each steel cap beam segment until the line shape formed by each steel cap beam segment is within the allowable error range of the complete steel cap beam design line shape;

[0023] Each component plate and two adjacent steel cap beam segments are welded in sequence to form a complete steel cap beam.

[0024] In one embodiment, the arrangement of the mounting base is specifically as follows:

[0025] Based on the design length of the complete steel cap beam, determine the size of the foundation bearing seat in the installation pedestal and assemble it on site;

[0026] A leveling steel plate is embedded on the top of the basic bearing seat to form a mounting base, and the leveling steel plate is leveled;

[0027] Select several segment monitoring points on the leveled leveling steel plate, and arrange multiple first jacks on the top of the leveling steel plate.

[0028] In one embodiment, the step of casting the pier column on the original soil after the capping casting treatment, hoisting the complete steel cap beam to the top of the pier column, and adjusting the installation elevation of the complete steel cap beam to the design elevation via a jacking mechanism located at the top of the pier column specifically includes:

[0029] After the capping hardness of the original soil meets the design requirements, two piers are cast, the jacking mechanism is embedded on the top of the pier and an outer steel plate is set around the pier;

[0030] Lower the hoisted complete steel cap beam so that both ends of the complete steel cap beam fall onto the jacking mechanisms of the two piers synchronously;

[0031] Adjust the height of the jacking mechanism until the installation elevation of both ends of the complete steel cap beam reaches the design elevation.

[0032] In one embodiment, the jacking mechanism includes a support platform arranged on the top of the pier column, and at least two second jacks radially symmetrical along the pier column are arranged on the support platform, and a pad is arranged on the top of the second jack.

[0033] In one embodiment, the complete steel cap beam is lowered and lifted so that both ends of the complete steel cap beam fall synchronously onto the jacking mechanisms of the two piers, specifically including:

[0034] Ropes are arranged on the complete steel cap beam, and the hoisting equipment lifts the complete steel cap beam until the height of the complete steel cap beam exceeds the height of the pier column;

[0035] The hoisting equipment moves to the pier column, and the rope is dragged to rotate the complete steel cap beam in the air until the center line of the complete steel cap beam coincides with the axis of the line connecting the center lines of the two pier columns;

[0036] Lower the complete steel cap beam until the bottom of the complete steel cap beam contacts the top of the outer steel plate;

[0037] Raise the second jack until it contacts the bottom of the complete steel cap beam.

[0038] In one embodiment, after the elevation adjustment of the complete steel cap beam is completed, the method further includes:

[0039] Weld the outer steel plate and the complete steel cap beam, and pour concrete and perform anti-corrosion treatment on the welds;

[0040] Filling micro-expanding fiber concrete into the complete steel cap beam;

[0041] After the concrete at the weld meets the design strength, remove the jacking mechanism.

[0042] In the second aspect, an embodiment of the present application provides a bridge, which is constructed based on the above-mentioned large-tonnage steel cap beam construction method for miscellaneous fill geology, and is characterized in that the bridge includes a complete steel cap beam and piers located at the bottom of both ends of the complete steel cap beam, and the outer periphery of the pier is provided with an outer steel plate.

[0043] The beneficial effects brought by the technical solution provided in the embodiments of the present application include:

[0044] By controlling the compaction degree of different replacement cushion layers, it helps to enhance the overall stability of the foundation, prevent the foundation from being deformed or damaged too much under load, and effectively reduce the settlement of the foundation. At the same time, when replacing the cushion of the original soil, the steel cap beam segments can be manufactured at the same time, which reduces the overall construction time, improves the construction efficiency, and has less impact on the existing operating lines. The steel cap beam segments are welded at the construction site, which can effectively reduce the risk of transportation;

[0045] By establishing a plane coordinate and elevation measurement and control network with the bridge as the main body at the construction site to weld the steel cap beam segments, and cooperating with the jacking mechanism cast on the top of the pier, the construction accuracy can be greatly improved, ensuring that the complete steel cap beam is in place at one time, and minimizing the impact on the existing operating line. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0047] Figure 1 A large-tonnage steel cap beam construction method for miscellaneous fill geology and a schematic diagram of the bridge flow provided in this application;

[0048] Figure 2 A schematic diagram of the structure of the jacking mechanism in a large-tonnage steel cap beam construction method for miscellaneous fill geology provided in this application.

[0049] In the figure: 1. Complete steel cap beam; 2. Pier column; 3. Support platform; 4. Second jack. DETAILED DESCRIPTION

[0050] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0051] On the first aspect, the embodiments of the present application provide a method for constructing large-tonnage steel cap beams in miscellaneous fill geology, which can solve the technical problems existing in the prior art that large-tonnage steel cap beams are constructed under the restrictive conditions of railway operating lines, the foundation of which is relatively loose and the bearing capacity is limited. At the same time, the lifting space and construction time are greatly limited, which seriously affects the installation efficiency and installation accuracy of the steel cap beam and also affects the operating railway.

[0052] Figure 1 A large-tonnage steel cap beam construction method for miscellaneous fill geology and a schematic diagram of the bridge flow provided in this application, Figure 2 A schematic diagram of the structure of the jacking mechanism in a large-tonnage steel cap beam construction method for miscellaneous fill geology provided in this application is shown in FIG. Figure 1 , Figure 2 As shown, the construction method in this application specifically includes:

[0053] S1: After leveling and excavation, the original soil is replaced by layers and capped with cast concrete, and the compaction degree of the replacement layer at the lower layer is greater than that of the replacement layer at the upper layer;

[0054] Generally speaking, the construction scope is mostly filled with miscellaneous fill soil, which includes construction waste such as broken bricks, rubble, rotten wood, domestic waste such as residual bones and furnace ash, and industrial waste such as slag and coal slag. The differences in these components lead to extremely uneven properties of the miscellaneous fill soil. The geology is loose and easy to collapse, which cannot meet the bearing requirements of the beam body. The geology within the construction scope is first replaced and its bearing capacity is improved before subsequent assembly and hoisting work. The compaction degree of the replacement cushion layer at the lower level is greater than that of the replacement cushion layer at the upper level. The higher compaction degree of the lower cushion layer means that its strength and stability are also higher, which helps to enhance the overall stability of the foundation, prevent the foundation from being deformed or damaged too much under the load, and can effectively reduce the settlement of the foundation.

[0055] S2: hoist the steel cap beam segments to the pre-arranged liftable installation pedestal, establish a plane coordinate and elevation measurement and control network with the bridge as the main body, and assemble the steel cap beam segments to form a complete steel cap beam 1 based on the plane coordinate and elevation measurement and control network;

[0056] The steel cap beam segments are first prefabricated and preliminarily spliced ​​(no welding is performed here) at the prefabrication site in accordance with the design requirements to form steel cap beam segments. The unwelded steel cap beam segments are then transported to the construction site. At the construction site, the spatial coordinates of the complete steel cap beam line are simplified into horizontal and vertical directions on the installation pedestal to facilitate monitoring and lifting after welding to form a complete steel cap beam 1. The soil treatment in step 1 and the cutting and splicing of the steel cap beam segments in step 2 are carried out simultaneously. After the capping hardness of the original soil is stabilized, the spliced ​​steel cap beam segments are transported to the construction site.

[0057] S3: Cast pier 2 on the original soil after capping casting, hoist the complete steel cap beam 1 to the top of pier 2, and adjust the installation elevation of the complete steel cap beam 1 to the designed elevation through the jacking mechanism located at the top of pier 2.

[0058] In a possible implementation manner, there are two groups of piers 2, which are used to respectively support the two ends of the complete steel cap beam 1. When casting the piers 2, a jacking mechanism is embedded on the top thereof. After the two ends of the complete steel cap beam 1 stably fall onto the two piers 2, the jacking mechanism is raised. At this time, the complete steel cap beam 1 is supported by the jacking mechanism, and the installation elevation of the complete steel cap beam 1 is adjusted by adjusting the lifting height of the jacking mechanism.

[0059] Furthermore, before or during the excavation of the original soil, it is necessary to first perform unit cutting and component manufacturing of the steel cap beam segments, specifically including:

[0060] Based on the design dimensions, process the various component plates of the steel cap beam segment;

[0061] Based on the installation sequence, each component plate is placed on the installation frame and fixed to form a single steel cap beam segment, wherein the ends of each component plate after fixing are spaced a certain distance apart;

[0062] The next steel cap beam segment is installed and fixed based on the previous fixed steel cap beam segment.

[0063] When dividing the steel cap beam into segments, the integrity of the structure is ensured as much as possible, which is conducive to the control of the linear shape of the complete steel cap beam 1 in the later stage. Taking into account many factors such as the lifting capacity of the factory lifting equipment, transportation routes, on-site working conditions, factory production and on-site lifting conditions, and the connection parts and interface staggered dimensions that meet the requirements of the specifications, in a possible implementation method, the complete steel cap beam 1 is divided into 5 steel cap beam segments along the length.

[0064] The assembly of the steel cap beam segment adopts the "positive installation method" to install the next steel cap beam segment with the previous steel cap beam segment as the benchmark. The "positive installation method" is a commonly used assembly method and will not be elaborated on here. When assembling a single steel cap beam segment, the installation frame is used as the outer tire and the cross partition of the steel cap beam segment is used as the inner tire. Each component plate is in place according to the longitudinal and transverse baselines, supplemented by reinforcement facilities to ensure accuracy (the position of each component plate is fixed here by reinforcement facilities, and no welding is done). It should be noted that the steel cap beam segment generally includes structures such as the top plate, the bottom plate, the rib plate and the web plate, which are collectively referred to as component plates here. In order to facilitate the adjustment of the relative positions of the component plates when the steel cap beam segments are connected, the end welds of the web plate, longitudinal ribs, etc. are left 200mm long and not welded for the time being. The position can be fixed with reinforcement facilities. After being transferred to the construction site, unified welding is carried out.

[0065] Furthermore, step S1 specifically includes:

[0066] S101: Based on the design drawings, excavate the original soil to a certain depth to form a foundation pit;

[0067] S102: Leveling and compacting the foundation pit and testing the bearing capacity of the foundation in the foundation pit to ensure that the bearing capacity of the foundation meets the bearing requirements;

[0068] S103: filling and compacting the replacement cushion material in the foundation pit to form a replacement cushion layer, and testing the bearing capacity of the replacement cushion layer;

[0069] S104: using the lower replacement bedding layer that has been replaced as the base, filling the upper replacement bedding layer until multiple replacement bedding layers are formed, wherein the compaction degree of the replacement bedding layer at the lower layer is greater than the compaction degree of the replacement bedding layer at the upper layer;

[0070] S105: Pour concrete above the topmost replacement cushion layer.

[0071] Clarify key information such as the location, size, depth and shape of the foundation pit, conduct on-site investigations, understand geological conditions, groundwater levels, surrounding buildings and underground pipelines, etc., to ensure the safety and feasibility of the excavation process, and excavate the original soil according to the excavation plan. Subsequently, level the bottom of the foundation pit to ensure that the bottom of the foundation pit is flat, without potholes and protrusions. According to the actual situation on site, compaction equipment and methods are used to compact the bottom of the foundation pit. Finally, the bearing capacity of the foundation in the foundation pit is tested. In one possible implementation method, the bearing capacity of the compacted foundation is not less than 150kPa.

[0072] After the foundation pit is compacted, graded crushed stone bricks are used for layered replacement. The number of layers is not specifically limited in this application, but it is necessary to replace and compact in layers. In a possible implementation, the total replacement depth is 1.5m, the foundation bearing capacity within the range of 0.7 to 1.5m below the top of the replacement cushion layer is not less than 220kPa, and the compaction degree is not less than 93%; the foundation bearing capacity within the range of 0.7m (including 0.7m) below the top of the replacement cushion layer is not less than 300kPa, and the compaction degree is not less than 95%. After the foundation treatment is completed and tested to be qualified, 30cm thick C20 plain concrete is poured for capping.

[0073] Furthermore, step S2 specifically includes:

[0074] S201: Arrange a liftable installation pedestal at the construction site so that the axial length of the installation pedestal is longer than the axial length of the complete steel cap beam, and sequentially hoist the steel cap beam segments onto the installation pedestal;

[0075] S202: Based on the design drawings and using surveying equipment, a plane coordinate and elevation measurement and control network with the bridge as the main body is established at the construction site;

[0076] S203: Using the plane coordinates and the height measurement and control network as the control reference, adjust the lifting height of the installation pedestal to independently adjust the elevation and horizontality of each steel cap beam segment until the line shape formed by each steel cap beam segment is within the allowable error range of the complete steel cap beam design line shape;

[0077] S204: Weld each component plate and two adjacent steel cap beam segments in sequence to form a complete steel cap beam 1.

[0078] Each steel cap beam segment is placed horizontally on the mounting pedestal, and the spatial coordinates of the linear shape of the complete steel cap beam 1 are simplified into horizontal and vertical directions on the mounting pedestal. In order to make the linear quality of the complete steel cap beam 1 more controllable, in a possible implementation manner, this step may involve the conversion of two plane coordinates and elevation control, that is, firstly establish prefabricated plane coordinates and prefabricated elevation measurement and control networks at the prefabrication site of the steel cap beam segment, and perform preliminary assembly of a single steel cap beam segment. When the steel cap beam segment is transferred to the construction site, the prefabricated plane coordinates and prefabricated elevation measurement and control networks are converted into plane coordinates and elevation measurement and control networks with the bridge as the main body. By adjusting the lifting height of the mounting pedestal, the elevation and horizontality of each steel cap beam segment can be independently adjusted to perform welding and measurement and control of multiple steel cap beam segments. This construction process enables the linear shape of the completed bridge to be intuitively set on the mounting pedestal, and the measurement and control means are simple and easy to master, and it is also convenient to control the one-time precise forming of the complete steel cap beam 1.

[0079] Furthermore, the arrangement of the mounting base is specifically as follows:

[0080] Based on the design length of the complete steel cap beam 1, determine the size of the basic bearing seat in the installation pedestal and assemble it on site;

[0081] A leveling steel plate is embedded on the top of the basic bearing seat to form a mounting base, and the leveling steel plate is leveled;

[0082] Select several segment monitoring points on the leveled leveling steel plate, and place and arrange multiple first jacks on the top of the leveling steel plate.

[0083] The length of the foundation bearing seat is not less than the length of the complete steel cap beam 1. It can be consistent with the manufacturing method of the steel cap beam segment, and is modularly manufactured and then spliced ​​on site to reduce the risk of transportation. A leveling steel plate is embedded on the top of the foundation bearing seat. The leveling steel plate is first adjusted to a horizontal state, and then a plurality of first jacks are placed on the leveling steel plate to respectively support the bottom of each steel cap beam segment, so as to facilitate independent adjustment of the elevation and horizontality of each steel cap beam segment.

[0084] In a possible implementation, in order to ensure force balance, each steel cap beam segment is provided with two first jacks at the bottom, respectively supporting the two ends of the single steel cap beam segment. The first jack can be pre-embedded in the mounting base or fixed by fixing measures, and no specific restrictions are made in this application.

[0085] After the steel cap beam segments are transported to the site, matching welding is carried out according to the segment monitoring points selected on site. Combined with the actual situation, the segment monitoring points can be the connection points of the steel cap beam segments. These points are the key positions where welding connections are required between the steel cap beam segments. By monitoring the position accuracy and welding quality of these points, the accurate connection between the segments and the stability of the overall structure can be ensured. They can also be stress concentration points. Some positions may cause stress concentration due to factors such as structural shape and load distribution. By setting monitoring points at these positions, stress changes can be monitored to avoid damage to the structure due to excessive stress. They can also be deformation monitoring points. During the welding process, due to factors such as thermal expansion and contraction and welding deformation, the steel cap beam segments may deform. By setting deformation monitoring points at key positions, deformation problems can be discovered and corrected in time. The above nodes can be flexibly selected according to actual needs, and no specific restrictions are made here.

[0086] Before welding, pay attention to controlling the size of the overall steel cap beam, and reserve a 50mm cutting allowance for the web and top and bottom plates of the last section of the steel cap beam (i.e. the end section of the steel cap beam) to avoid the overall length of the steel cap beam being shortened due to temperature, environmental and other factors.

[0087] Furthermore, step S3 specifically includes:

[0088] S301: After the capping casting hardness of the original soil meets the design requirements, two piers 2 are cast, a jacking mechanism is embedded in the top of the pier 2, and an outer steel plate is arranged around the pier 2;

[0089] S302: lowering the lifted complete steel cap beam 1 so that both ends of the complete steel cap beam 1 fall synchronously onto the jacking mechanisms of the two piers 2;

[0090] S303: Adjust the height of the jacking mechanism until the installation elevations of both ends of the complete steel cap beam 1 reach the design elevations.

[0091] The jacking mechanism comprises a supporting platform 3 arranged on the top of the pier column 2, on which at least two second jacks 4 radially symmetrical along the pier column 2 are arranged, and on the top of the second jacks 4 a pad is arranged.

[0092] When pouring the top of the pier 2, two sets of corbel climbing cones are embedded on each pier 2 to fix a supporting corbel respectively. The second jack 4 is set on the supporting corbel. The top surface elevation of the corbel is measured before the steel cap beam is hoisted. When there is a slight deviation, it is adjusted by using steel plate pads to ensure that the top surfaces of the four corbels have the same elevation. Then the complete steel cap beam 1 is lowered so that its two ends fall at the same time and are supported by the second jack 4 on the four corbels. When the complete steel cap beam 1 falls onto the jacking mechanism, the jacking mechanism is used to adjust the height of the two ends of the complete steel cap beam 1. After the adjustment is completed, necessary inspections and tests are carried out to ensure that the position and height of the complete steel cap beam 1 meet the design requirements.

[0093] In the above steps, an outer steel plate is arranged on the periphery of the pier 2 to increase the structural strength and stability of the pier 2 and also improve the aesthetics. The outer steel plate needs to fit tightly with the pier 2 and be fixed by welding or bolting, etc., which will not be elaborated here.

[0094] Furthermore, the above step S302 specifically includes:

[0095] S3021: Ropes are arranged on the complete steel cap beam 1, and the complete steel cap beam 1 is lifted by the lifting equipment until the height of the complete steel cap beam 1 exceeds the height of the pier 2;

[0096] S3022: The hoisting equipment moves to the pier 2, and the rope is dragged to rotate the complete steel cap beam 1 in the air until the center line of the complete steel cap beam 1 coincides with the axis of the connecting line of the center lines of the two piers 2;

[0097] S3023: lower the complete steel cap beam 1 until the bottom of the complete steel cap beam 1 contacts the top of the outer steel plate;

[0098] S3024: Raise the second jack 4 until the second jack 4 contacts the bottom of the complete steel cap beam 1.

[0099] After the crane lifts the complete steel cap beam 1 to the designated position, the commander will direct the rod to be slowly turned, and at the same time, the complete steel cap beam 1 will be rotated by manually pulling the rope, and the lifted complete steel cap beam 1 will be slowly turned to the upper side of the center of the railway line, and the center line of the complete steel cap beam 1 will roughly coincide with the axis of the center line connection of the two piers 2, and the two ends of the complete steel cap beam 1 will be aligned with the pier top positions of the two piers 2, and then the complete steel cap beam 1 will be lowered to the top of the jacking mechanism, first ensuring that the two ends of the complete steel cap beam 1 are simultaneously and smoothly lowered to the top position of the outer steel plate, and then adjusted by the second jack 4, at this time, the complete steel cap beam 1 is completely supported by the jacking mechanism.

[0100] Furthermore, after the elevation adjustment of the complete steel cap beam 1 is completed, it also includes:

[0101] Weld the outer steel plate and the complete steel cap beam 1, and pour concrete and perform anti-corrosion treatment on the welds;

[0102] Filling the interior of the complete steel cap beam 1 with micro-expanding fiber concrete;

[0103] After the concrete at the weld meets the design strength, remove the jacking mechanism.

[0104] After the adjustment, there may be a certain gap between the outer steel plate and the complete steel cap beam 1. Welding treatment is carried out here to cooperate with concrete pouring, and anti-corrosion coating is applied to the weld and the outer steel plate as a whole. The C50 micro-expansive fiber concrete is poured inside the steel cap beam using a car pump. After the concrete at the junction of the complete steel cap beam 1 and the pier 2 reaches the design strength, the jacking mechanism is removed, the force conversion is carried out, and the installation of the complete steel cap beam 1 is completed.

[0105] On the second aspect, the present application also provides a bridge constructed by the above-mentioned large-tonnage steel cap beam construction method for miscellaneous fill geology, the bridge includes a complete steel cap beam 1 and piers 2 located at the bottom of both ends of the complete steel cap beam 1, and the outer periphery of the pier 2 is provided with an outer steel plate.

[0106] In the description of the present application, it should be noted that the terms "upper", "lower", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. Unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be a connection between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.

[0107] It should be noted that, in this application, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0108] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.

Claims

1. A method for constructing a large-tonnage steel cap beam in miscellaneous fill geology, characterized in that: The construction method comprises: After leveling and excavation, the original soil is replaced by layers and capped with cast concrete, and the compaction degree of the replacement layer at the lower layer is greater than that of the replacement layer at the upper layer; Lifting the steel cap beam segments to a pre-arranged escalable mounting pedestal, establishing a plane coordinate and elevation measurement and control network with the bridge as the main body, and assembling the steel cap beam segments to form a complete steel cap beam based on the plane coordinate and elevation measurement and control network (1); The pier (2) is cast on the original soil after the capping casting treatment, the complete steel cap beam (1) is hoisted to the top of the pier (2), and the installation elevation of the complete steel cap beam (1) is adjusted to the designed elevation via a jacking mechanism located at the top of the pier (2).

2. A method for constructing a large-tonnage steel cap beam in miscellaneous fill geology as claimed in claim 1, characterized in that: Before excavating the original soil, it also includes: Based on the design dimensions, process the various component plates of the steel cap beam segment; Based on the installation sequence, each component plate is placed on the installation frame and fixed to form a single steel cap beam segment, wherein the ends of each component plate after fixing are spaced a certain distance apart; The next steel cap beam segment is installed and fixed based on the previous fixed steel cap beam segment.

3. The method for constructing a large-tonnage steel cap beam in miscellaneous fill geology as claimed in claim 1, characterized in that: The original soil after leveling and excavation is subjected to layered cushion replacement and capping pouring treatment, and the compaction degree of the cushion replacement layer at the lower layer is greater than the compaction degree of the cushion replacement layer at the upper layer, specifically including: Based on the design drawings, excavate the original soil to a certain depth to form a foundation pit; Level and compact the foundation pit and test the bearing capacity of the foundation in the foundation pit to ensure that the bearing capacity of the foundation meets the bearing requirements; Fill and compact the replacement cushion material in the foundation pit to form a replacement cushion layer, and test the bearing capacity of the replacement cushion layer; Using the lower replacement bedding layer that has been replaced as the base, fill the upper replacement bedding layer until multiple replacement bedding layers are formed, wherein the compaction degree of the replacement bedding layer at the lower layer is greater than that of the replacement bedding layer at the upper layer; Pour the concrete above the topmost replacement pad.

4. The method for constructing a large-tonnage steel cap beam in miscellaneous fill geology as claimed in claim 1, characterized in that: The method comprises hoisting the steel cap beam segments to a pre-arranged escalable mounting pedestal, establishing a plane coordinate and elevation measurement and control network with the bridge as the main body, and assembling the steel cap beam segments to form a complete steel cap beam (1) based on the plane coordinate and elevation measurement and control network. Specifically, the method comprises: Arrange a liftable installation pedestal at the construction site so that the axial length of the installation pedestal is longer than the axial length of the complete steel cap beam, and hoist the steel cap beam segments onto the installation pedestal in sequence; Based on the design drawings and using surveying equipment, a plane coordinate and elevation measurement and control network with the bridge as the main body is established at the construction site; Using the plane coordinates and the height measurement and control network as the control reference, adjust the lifting height of the installation pedestal to independently adjust the elevation and horizontality of each steel cap beam segment until the line shape formed by each steel cap beam segment is within the allowable error range of the complete steel cap beam design line shape; The component plates and two adjacent steel cap beam segments are welded in sequence to form a complete steel cap beam (1).

5. A method for constructing a large-tonnage steel cap beam in miscellaneous fill geology as claimed in claim 4, characterized in that: The specific arrangement of the mounting base is as follows: Based on the designed length of the complete steel cap beam (1), the size of the basic bearing seat in the installation pedestal is determined and assembled on site; A leveling steel plate is embedded on the top of the basic bearing seat to form a mounting base, and the leveling steel plate is leveled; Select several segment monitoring points on the leveled leveling steel plate, and arrange multiple first jacks on the top of the leveling steel plate.

6. The method for constructing a large-tonnage steel cap beam in miscellaneous fill geology as claimed in claim 1, characterized in that: The method comprises: casting the pier column (2) on the original soil after the capping casting treatment, hoisting the complete steel cap beam (1) to the top of the pier column (2), and adjusting the installation elevation of the complete steel cap beam (1) to the designed elevation via a jacking mechanism located at the top of the pier column (2), specifically comprising: After the capping casting hardness of the original soil meets the design requirements, two piers (2) are cast, a jacking mechanism is pre-embedded on the top of the pier (2) and an outer steel plate is arranged on the outer periphery of the pier (2); Lowering the hoisted complete steel cap beam (1) so that both ends of the complete steel cap beam (1) fall synchronously onto the jacking mechanisms of the two piers (2); Adjust the height of the lifting mechanism until the installation elevation of both ends of the complete steel cap beam (1) reaches the designed elevation.

7. A method for constructing a large-tonnage steel cap beam in miscellaneous fill geology as claimed in claim 6, characterized in that: The jacking mechanism comprises a support platform (3) arranged on the top of the pier column (2), the support platform (3) being provided with at least two second jacks (4) which are radially symmetrical along the pier column (2), and a pad is provided on the top of the second jack (4).

8. A method for constructing a large-tonnage steel cap beam in miscellaneous fill geology as claimed in claim 7, characterized in that: The complete steel cap beam (1) is lowered and lifted, so that both ends of the complete steel cap beam (1) are synchronously dropped onto the jacking mechanisms of the two piers (2), specifically comprising: Ropes are arranged on the complete steel cap beam (1), and the complete steel cap beam (1) is lifted by a lifting device until the height of the complete steel cap beam (1) exceeds the height of the pier column (2); The hoisting equipment moves to the pier (2), and the rope is dragged to rotate the complete steel cap beam (1) in the air until the center line of the complete steel cap beam (1) coincides with the axis of the center line connecting the two piers (2); Lowering the complete steel cap beam (1) until the bottom of the complete steel cap beam (1) contacts the top of the outer steel plate; Raise the second jack (4) until the second jack (4) abuts against the bottom of the complete steel cap beam (1).

9. A method for constructing a large-tonnage steel cap beam in miscellaneous fill geology as claimed in claim 8, characterized in that: After the elevation adjustment of the complete steel cap beam (1) is completed, it also includes: Welding the outer steel plate and the complete steel cap beam (1), and pouring concrete and performing anti-corrosion treatment on the welds; Filling the micro-expanding fiber concrete into the complete steel cap beam (1); After the concrete at the weld meets the design strength, remove the jacking mechanism.

10. A bridge constructed by the large-tonnage steel capping girder construction method for miscellaneous fill geology according to any one of claims 1 to 9, characterized in that: The bridge comprises a complete steel cap beam (1) and piers (2) located at the bottom of both ends of the complete steel cap beam (1), and the outer periphery of the piers (2) is provided with an outer steel plate.

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